Dishwashers usually have at least one washing container and spray devices located therein, wherein the spray devices are loaded with liquid conveyed by a recirculation pump in order to act upon items to be washed in the washing container with washing fluid. In the known dishwashers, a plurality of wash programs composed of the partial program steps pre-wash, clean, intermediate rinse, clear rinse and dry can usually be selected by means of a program controller. Since the washing fluid accumulates washing residues during the cleaning phases, filter systems are provided in the water circuit of the dishwasher through which washing water circulated by the recirculation pump is passed continuously.
The known dishwashers have the disadvantage that the filter systems can become clogged with washing residues in the course of the washing program. This results in back-contamination of the items to be washed as a result of size reduction and fine distribution of the washing residues deposited at the filter systems and thus reduces the cleaning effect of the dishwasher. Obstructions can also occur in the washing liquid circuit, whereby the cleaning function of the filter systems is impaired. Another disadvantage is that as a result of the obstructions in the washing liquid circuit and the lengthening of the wash program, the energy consumption of the dishwasher required to achieve a satisfactory cleaning result is increased.